minix/lib/libc/include/reentrant.h

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/* $NetBSD: reentrant.h,v 1.15 2012/06/03 21:27:30 joerg Exp $ */
/*-
* Copyright (c) 1997, 1998, 2003 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by J.T. Conklin, by Nathan J. Williams, and by Jason R. Thorpe.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Requirements:
*
* 1. The thread safe mechanism should be lightweight so the library can
* be used by non-threaded applications without unreasonable overhead.
*
* 2. There should be no dependency on a thread engine for non-threaded
* applications.
*
* 3. There should be no dependency on any particular thread engine.
*
* 4. The library should be able to be compiled without support for thread
* safety.
*
*
* Rationale:
*
* One approach for thread safety is to provide discrete versions of the
* library: one thread safe, the other not. The disadvantage of this is
* that libc is rather large, and two copies of a library which are 99%+
* identical is not an efficent use of resources.
*
* Another approach is to provide a single thread safe library. However,
* it should not add significant run time or code size overhead to non-
* threaded applications.
*
* Since the NetBSD C library is used in other projects, it should be
* easy to replace the mutual exclusion primitives with ones provided by
* another system. Similarly, it should also be easy to remove all
* support for thread safety completely if the target environment does
* not support threads.
*
*
* Implementation Details:
*
* The thread primitives used by the library (mutex_t, mutex_lock, etc.)
* are macros which expand to the cooresponding primitives provided by
* the thread engine or to nothing. The latter is used so that code is
* not unreasonably cluttered with #ifdefs when all thread safe support
* is removed.
*
* The thread macros can be directly mapped to the mutex primitives from
* pthreads, however it should be reasonably easy to wrap another mutex
* implementation so it presents a similar interface.
*
* The thread functions operate by dispatching to symbols which are, by
* default, weak-aliased to no-op functions in thread-stub/thread-stub.c
* (some uses of thread operations are conditional on __isthreaded, but
* not all of them are).
*
* When the thread library is linked in, it provides strong-alias versions
* of those symbols which dispatch to its own real thread operations.
*
*/
#ifdef _REENTRANT
/*
* Abstract thread interface for thread-safe libraries. These routines
* will use stubs in libc if the application is not linked against the
* pthread library, and the real function in the pthread library if it
* is.
*/
#include <pthread.h>
#include <signal.h>
#define mutex_t pthread_mutex_t
#define MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
#define mutexattr_t pthread_mutexattr_t
#define MUTEX_TYPE_NORMAL PTHREAD_MUTEX_NORMAL
#define MUTEX_TYPE_ERRORCHECK PTHREAD_MUTEX_ERRORCHECK
#define MUTEX_TYPE_RECURSIVE PTHREAD_MUTEX_RECURSIVE
#define cond_t pthread_cond_t
#define COND_INITIALIZER PTHREAD_COND_INITIALIZER
#define condattr_t pthread_condattr_t
#define rwlock_t pthread_rwlock_t
#define RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER
#define rwlockattr_t pthread_rwlockattr_t
#define thread_key_t pthread_key_t
#define thr_t pthread_t
#define thrattr_t pthread_attr_t
#define once_t pthread_once_t
#define ONCE_INITIALIZER PTHREAD_ONCE_INIT
#ifndef __LIBC_THREAD_STUBS
__BEGIN_DECLS
int __libc_mutex_init(mutex_t *, const mutexattr_t *);
int __libc_mutex_lock(mutex_t *);
int __libc_mutex_trylock(mutex_t *);
int __libc_mutex_unlock(mutex_t *);
int __libc_mutex_destroy(mutex_t *);
int __libc_mutexattr_init(mutexattr_t *);
int __libc_mutexattr_settype(mutexattr_t *, int);
int __libc_mutexattr_destroy(mutexattr_t *);
__END_DECLS
#define mutex_init(m, a) __libc_mutex_init((m), (a))
#define mutex_lock(m) __libc_mutex_lock((m))
#define mutex_trylock(m) __libc_mutex_trylock((m))
#define mutex_unlock(m) __libc_mutex_unlock((m))
#define mutex_destroy(m) __libc_mutex_destroy((m))
#define mutexattr_init(ma) __libc_mutexattr_init((ma))
#define mutexattr_settype(ma, t) __libc_mutexattr_settype((ma), (t))
#define mutexattr_destroy(ma) __libc_mutexattr_destroy((ma))
__BEGIN_DECLS
int __libc_cond_init(cond_t *, const condattr_t *);
int __libc_cond_signal(cond_t *);
int __libc_cond_broadcast(cond_t *);
int __libc_cond_wait(cond_t *, mutex_t *);
#ifndef __LIBC12_SOURCE__
int __libc_cond_timedwait(cond_t *, mutex_t *, const struct timespec *);
#endif
int __libc_cond_destroy(cond_t *);
__END_DECLS
#define cond_init(c, t, a) __libc_cond_init((c), (a))
#define cond_signal(c) __libc_cond_signal((c))
#define cond_broadcast(c) __libc_cond_broadcast((c))
#define cond_wait(c, m) __libc_cond_wait((c), (m))
#define cond_timedwait(c, m, t) __libc_cond_timedwait((c), (m), (t))
#define cond_destroy(c) __libc_cond_destroy((c))
__BEGIN_DECLS
int __libc_rwlock_init(rwlock_t *, const rwlockattr_t *);
int __libc_rwlock_rdlock(rwlock_t *);
int __libc_rwlock_wrlock(rwlock_t *);
int __libc_rwlock_tryrdlock(rwlock_t *);
int __libc_rwlock_trywrlock(rwlock_t *);
int __libc_rwlock_unlock(rwlock_t *);
int __libc_rwlock_destroy(rwlock_t *);
__END_DECLS
#define rwlock_init(l, a) __libc_rwlock_init((l), (a))
#define rwlock_rdlock(l) __libc_rwlock_rdlock((l))
#define rwlock_wrlock(l) __libc_rwlock_wrlock((l))
#define rwlock_tryrdlock(l) __libc_rwlock_tryrdlock((l))
#define rwlock_trywrlock(l) __libc_rwlock_trywrlock((l))
#define rwlock_unlock(l) __libc_rwlock_unlock((l))
#define rwlock_destroy(l) __libc_rwlock_destroy((l))
__BEGIN_DECLS
int __libc_thr_keycreate(thread_key_t *, void (*)(void *));
int __libc_thr_setspecific(thread_key_t, const void *);
void *__libc_thr_getspecific(thread_key_t);
int __libc_thr_keydelete(thread_key_t);
__END_DECLS
#define thr_keycreate(k, d) __libc_thr_keycreate((k), (d))
#define thr_setspecific(k, p) __libc_thr_setspecific((k), (p))
#define thr_getspecific(k) __libc_thr_getspecific((k))
#define thr_keydelete(k) __libc_thr_keydelete((k))
__BEGIN_DECLS
int __libc_thr_once(once_t *, void (*)(void));
int __libc_thr_sigsetmask(int, const sigset_t *, sigset_t *);
thr_t __libc_thr_self(void);
int __libc_thr_yield(void);
void __libc_thr_create(thr_t *, const thrattr_t *,
void *(*)(void *), void *);
void __libc_thr_exit(void *) __attribute__((__noreturn__));
int *__libc_thr_errno(void);
int __libc_thr_setcancelstate(int, int *);
unsigned int __libc_thr_curcpu(void);
extern int __isthreaded;
__END_DECLS
#define thr_once(o, f) __libc_thr_once((o), (f))
#define thr_sigsetmask(f, n, o) __libc_thr_sigsetmask((f), (n), (o))
#define thr_self() __libc_thr_self()
#define thr_yield() __libc_thr_yield()
#define thr_create(tp, ta, f, a) __libc_thr_create((tp), (ta), (f), (a))
#define thr_exit(v) __libc_thr_exit((v))
#define thr_errno() __libc_thr_errno()
#define thr_enabled() (__isthreaded)
#define thr_setcancelstate(n, o) __libc_thr_setcancelstate((n),(o))
#define thr_curcpu() __libc_thr_curcpu()
#endif /* __LIBC_THREAD_STUBS */
#define FLOCKFILE(fp) __flockfile_internal(fp, 1)
#define FUNLOCKFILE(fp) __funlockfile_internal(fp, 1)
#else /* _REENTRANT */
#define mutex_init(m, a)
#define mutex_lock(m)
#define mutex_trylock(m)
#define mutex_unlock(m)
#define mutex_destroy(m)
#define cond_init(c, t, a)
#define cond_signal(c)
#define cond_broadcast(c)
#define cond_wait(c, m)
#define cond_timedwait(c, m, t)
#define cond_destroy(c)
#define rwlock_init(l, a)
#define rwlock_rdlock(l)
#define rwlock_wrlock(l)
#define rwlock_tryrdlock(l)
#define rwlock_trywrlock(l)
#define rwlock_unlock(l)
#define rwlock_destroy(l)
#define thr_keycreate(k, d)
#define thr_setspecific(k, p)
#define thr_getspecific(k)
#define thr_keydelete(k)
#if !defined(__minix)
static inline int
thr_once(once_t *once_control, void (*routine)(void))
{
if (__predict_false(once_control->pto_done == 0)) {
(*routine)();
once_control->pto_done = 1;
}
return 0;
}
#endif /* defined(__minix) */
#define thr_sigsetmask(f, n, o)
#define thr_self()
#define thr_errno()
#define thr_curcpu() ((unsigned int)0)
#define FLOCKFILE(fp)
#define FUNLOCKFILE(fp)
#endif /* _REENTRANT */